Temporal trends of Surface water across Indian Rivers & Basins¶

This dataset quantifies the extent and rate of annual change in surface water area (SWA) across India's rivers and basins over 30 years from 1991 to 2020. It does so by season (annual dry, wet and permanent water, based on India's seasons) and at two spatial scales: the river basin scale (1516 level-7 basins from HydroBASINS) and the finer river reach scale (68,367 reaches). This dataset is derived from the historical time series of monthly surface water occurrence by JRC's Global Surface Water Explorer. You can read additional details about the dataset in the paper and access the dataset here.

The authors have also provided a dataset page and an earth engine app to analyze the dataset further.

These are available as the following GEE assets

Annual rate of change of surface water area, by season
- Reaches: projects/sat-io/open-datasets/indian_rivers/riverchanges/txsTrends
- Basins: projects/sat-io/open-datasets/indian_rivers/riverchanges/basinsTrends

Expand to show Attributes for Annual rate of change of surface water area feature collections

Attribute	Description
HYBAS_ID or txId	Feature's unique identifier. HYBAS_ID is for basins. It is the basin's identifier HYBAS_ID in the HydroBASINS dataset txId is for transects. It is the '' concatenated string derived from the longitude and latitude values, truncated to 4 decimals, of the transect's median point. Specifically, it is "_xx.xxxx_yy.yyyy" where xx.xxxx and yy.yyyy are the median's longitude and latitude values truncated to 4 decimals.
season	Denotes the season, in "sss_mmm" format, where "sss" denotes the season: "dry" for dry, "wet" for wet and "prm" for permanent "mmm" denotes the span of the season in calendar months: "fma" is for dry season of February-March-April, "ond" is for wet (post-monsoon) season of October-November-December and "DnW" is for permanent which is dry AND wet season.
sl_perYr	Regression slope of the surface water area vs. year Sen's slope regression analysis, and "perYr" denotes its units, per year.
offset	Regression offset of the surface water area vs. year Sen's slope regression analysis.
tsPtCount	Number of time-points included in the Sen's slope regression analysis.
system:index	GEE system-generated unique identifier.

Time series of annual surface water area, by season
- Reaches: projects/sat-io/open-datasets/indian_rivers/riverchanges/mainlandIndia_areasTs_txs
- Basins: projects/sat-io/open-datasets/indian_rivers/riverchanges/mainlandIndia_areasTs_basinsL7

Expand to show Attributes for Time series of annual surface water area feature collections

Attribute	Description
HYBAS_ID or txId	Feature's unique identifier. - HYBAS_ID is for basins. It is the basin's identifier HYBAS_ID in the HydroBASINS dataset. - txId is for transects. It is the '' concatenated string derived from the longitude and latitude values, truncated to 4 decimals, of the transect's median point. Specifically, it is "_xx.xxxx_yy.yyyy" where xx.xxxx and yy.yyyy are the median's longitude and latitude values truncated to 4 decimals.
season	Denotes the season, in "sss_mmm" format. - "sss" denotes the season: "dry" for dry, "wet" for wet, and "prm" for permanent. - "mmm" denotes the span of the season in calendar months: "fma" is for the dry season of February-March-April, "ond" is for the wet (post-monsoon) season of October-November-December, and "DnW" is for permanent which is dry AND wet season.
year	Year.
water_ha	Area of water pixels in the feature, in hectares.
notwater_ha	Area of notwater pixels in the feature, in hectares.
nodata_ha	Area of nodata pixels in the feature, in hectares.
nodataFrac	Proportion of the feature's area with nodata pixels.
system:index	GEE system-generated unique identifier.

Time series of annual surface water occurrence, by season: projects/sat-io/open-datasets/indian_rivers/riverchanges/waterOccSeasComps

Expand to show band information for Time series of annual surface water image collection

Bands	Description
drySeasCompos_fma	Each pixel in these bands have one of 3 integer values (following the convention in the JRC water dataset, Pekel et al. 2016)
wetSeasCompos_ond	* `2`: a pixel with valid data and containing water (denoting a "water" pixel)
prmSeasCompos_DnW	* `1`: a pixel with valid data and not containing water (denoting a "notwater" pixel)
	* `0`: a pixel with no valid data (denoting a "nodata" pixel)

Expand to show attributes for Time series of annual surface water image collection

Properties	Description
year	year of the image.
monsoonYearStartMonth	Number (between 1-12) of the month when monsoon (or, hydrological) year starts. It is 6, indicating June, and is the same for all images. A year is taken to be June to May in this analysis.
drySeasMonthsOffset	Number of months after `monsoonYearStartMonth` when dry season starts. It is 8, indicating February.
drySeasMonthsTag	Suffix tag, in names of image bands, table columns, etc., indicating the 3 months of the dry season.
wetSeasMonthsOffset	Number of months after `monsoonYearStartMonth` when wet season starts. It is 4, indicating October.
wetSeasMonthsTag	Suffix tag, in names of image bands, table columns, etc., indicating the 3 months of the wet season.

More details and resources:

Published data repository (excluding the time series of annual surface water occurrence)	https://doi.org/10.5281/zenodo.7803903
Published Earth Engine code behind the analysis	https://doi.org/10.5281/zenodo.7839588
Published data description	https://doi.org/10.1016/j.dib.2023.109991
Interactive visualization, and more	https://sites.google.com/view/surface-water-trends-india/

Citation¶

Koulgi P, Jumani S. Dataset of temporal trends of surface water area across India's rivers and basins. Data Brief. 2023 Dec 19;52:109991.
doi: 10.1016/j.dib.2023.109991. PMID: 38235174; PMCID: PMC10792741.

indian_basins

Earth Engine Snippet if dataset already in GEE¶

var reachTrends = ee.FeatureCollection('projects/sat-io/open-datasets/indian_rivers/riverchanges/txsTrends');
var reachAreaTimeseries = ee.FeatureCollection('projects/sat-io/open-datasets/indian_rivers/riverchanges/mainlandIndia_areasTs_txs');
var basTrends = ee.FeatureCollection('projects/sat-io/open-datasets/indian_rivers/riverchanges/basinsTrends');
var basAreaTimeseries = ee.FeatureCollection('projects/sat-io/open-datasets/indian_rivers/riverchanges/mainlandIndia_areasTs_basinsL7');
var annualWaterOccSeasComps = ee.ImageCollection('projects/sat-io/open-datasets/indian_rivers/riverchanges/waterOccSeasComps');

var brewer7ClPuOr = ['b35806', 'f1a340', 'fee0b6', 'f7f7f7', 'd8daeb', '998ec3', '542788'];
var empty = ee.Image().byte();

var reachTrendsDrySeason = reachTrends.filter(ee.Filter.eq('season', 'dry_fma'));
var fillsreach = empty.paint(reachTrendsDrySeason, 'sl_perYr');
Map.addLayer(fillsreach, {palette: brewer7ClPuOr, min: -0.02, max: 0.02}, 'dry_fma_reach');
Map.setCenter(79.49959, 16.63471, 14);

var basTrendDrySeason = basTrends.filter(ee.Filter.and(ee.Filter.eq('HYBAS_ID', 4071092530), ee.Filter.eq('season', 'dry_fma')));
var fillsBas = empty.paint(basTrendDrySeason, 'sl_perYr');
Map.addLayer(fillsBas, {palette: brewer7ClPuOr, min: -75, max: 75}, 'dry_fma_bas', false);

Sample code: https://code.earthengine.google.com/?scriptPath=users/sat-io/awesome-gee-catalog-examples:hydrology/TEMPORAL-TRENDS-INDIAN-RIVERS-BASINS

Earth Engine app: Access the Earth Engine app here and the data page here

License¶

These datasets are provided under a CC-BY-4.0 license.

Provided by: Koulgi and Jumani 2023

Curated in GEE by: Pradeep Koulgi and Samapriya Roy

Keywords : surface water, river reaches, river basins, time series,india

Last updated on GEE: 2024-02-16